8 Series Single block with Stainless Steel cheeks and Aluminum "universal circuit" ball bearing sheave. Aluminum sheave run on Delrin(tm) ball bearings for a very strong yet low-friction sheave. Stainless Steel D shackle run on a swivel head that may be locked in plate to avoid line twist. Bolted construction allows for easy maintainence. Sheave Dia. 2 3/8" (60mm), Thickness 1 3/32" (28mm), Width 2 3/8" (60mm), Length 5 5/8" (143mm), SWL 2750 lbs (1250kg), Weight 13.8oz (391g), Max Line 9/16" (14mm)